Clock on whiteboard

Whiteboard Clock is a device that writes the current time with a whiteboard marker. Every X (by default - 5) minutes, it erases the previous time and writes a new one.

The creator of the gadget describes its design and publishes the source code for controlling the motors.


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Yellow and red details in the design are printed on a 3D printer ( source code of 3D models for OpenSCAD).



In addition to these, two motors are required to control the "hand" and another motor to lift the structure to the desired height.

The device is controlled by the PIC16F1454 microcontroller, which receives commands from a computer over the radio at 433 MHz from another similar microcontroller. The USB bus is powered only. That is, the gadget, in principle, can be made mobile if you provide it with an autonomous power source.



Small ASCII text fragments are transmitted by radio. Under Linux, these transfers are initiated by commands like "echo 12:34 > /dev/whiteboard" . Such a team will write on the blackboard time 12:34 .

The author has developed his own simple protocol for data transfer, where “1” corresponds to a signal of 0.2 ms and 0.1 ms of silence, and “0” - 0.1 ms of a signal and 0.2 ms of silence. Each message is sent multiple times for error correction.



The font is determined by simply specifying the X and Y coordinates ( code ). They are processed by a C ++ program that converts the coordinates into a motion marker.



This homemade clock is reminiscent of the project Plotclock a year ago on the Arduino. By the way, even more detailed assembly instructions have been published for it.